Neuronal characteristics of mouse C1300 neuroblastoma cells in culture are being studied. Mechanism of neurotransmitter uptake, storage and release are being investigated in dividing undifferentiated and in nondividing differentiated cells. It is hoped that the information obtained will contribute to understanding the mechanisms involved in differentiation from a tumor cell to a more mature cell. Furthermore, knowledge about the functional capabilities of neuroblastoma cells may lead to therapeutic control of this type of cancer.